Arc protector for high voltage insulators



y 1966 G. HILGARTH ETAL 3,252,054

ARC PROTECTOR FOR HIGH VOLTAGE INSULATORS Filed Oct. 15, 1964 3 Sheets-Sheet 1 Fig. I 911 .712 van/0r:

m A tbr v May 17, 1966 G. HILGARTH ETAL 3,252,054

ARC PROTECTOR FOR HIGH VOLTAGE INSULATORS 3 Sheets-Sheet 2 Filed Oct. 15, 1964 .70 van far Gut/fixer $90 16 and Ernst 24m 77\e1/- Afar/1e May 17, 1966 G. HILGARTH ETAL ARC PROTECTOR FOR HIGH VOLTAGE INSULATORS Filed Oct. 15, 1964 3 Sheets-Sheet 5 United States Patent K Claims. (Cl. 317-72) The invention relates to high voltage overhead electric power transmission lines, and relates more particularly to insulator chains for such transmission lines that are suspended from crossbars of a pole and in turn suspend conductors. Still more particularly,'the invention relates to are protectors or protective guards to protect the insulator chains from arcing effects.

An insulator chain [for overhead high voltage electric power transmission line from 220 kv. up generally is provided near the conductor with a protective ring which is made from tubularor rolled stock. These rings serve the purpose to controlthe voltage distribution along the length of the chain, to restrain a premature corona start and, in the event of a flashover, to take on the arc in order to keep it from the porcelain insulators.

Tests have shown, however, that protective rings of this type do not afford enough protection where large current is applied during long application periods, for instance 30 kiloamperes per second, resulting in damage to the porcelain.

This insuflicient protection contrasts unfavorably with guards in the form of spiral armatures which are positioned near the crossbar. These spiral armatures are made of round steel, and are in strut form. The excellent protection afforded by these spiral armatures appears to be due to the perfect stabilization of the arc column near the bottom thereof.

As is well known, the arc has-the tendency to burn along the prolongation of the arcing horn as conditioned by the electro-dynamic forces. In order to achieve the aforesaid desirable stabilization of the arc, there is needed a long, preferably slender arcing born.

In connection with arc in view of the manifold operation possibilities, generally not possible to use such long, slender arcing horns. While the control of the arc with respect to insulator protection would considerably be increased by their use, the distribution of the voltage along the chain would be influenced negatively, and likewise there would be influenced negatively the critical voltage at which the corona starts, and also the fla-shover potential.

For this reason, where protective rings are used, there are usually not used any long slender arcing horns, and the reduced protection against arcing is compensated for by increasing the diameter of the ring. This results in a partial improvement, but does not provide a solution of the problem.

It is accordingly among the principal objects of the into Kronprinz ,Aktiengesell- Germany, a corporation of Claims vention to provide protective rings which avoid the drawbacks that attended such use heretofore.

It is a further object of the invention tective rings with movable arcing horns.

It is another object of the invention to provide such movable arcing horns which during normal application are positioned in the shadow of the electric field and therefore exert little or no influence on the commencement of the corona; the field is advantageously controlled by the shape of the ring, free from disturbance by any protruding object. 2

Further objects and advantages of the invention will be set forth in part in the following specification and in to provide pro- Wolfenbuttel, and Ernst Decker, Hilprotective rings, however it is,

panying drawings and for ments of the same being part will be obvious therefrom without being specifically referred to, the same being realized and attained as pointed out in the claims hereof.

In the construction in accordance with the invention, the movable arcing horn upon the occurrence of the flashover will automatically, depending on the construction, either be moved about a hinge or by moved linearly.

Preferably, the horn will be unblocked for movement by the arc itself, for instance by melting of an arresting pin disposed in the circuit, or by overcoming gravity.

This offers the advantage to make the movement of the movable horn dependent on the value of the electric current and on the period of current flow. During the occurrences of only small currents and short arcing periods, where there exists no hazard of damage to the porcelain, the movable arcing horn will not be moved at all.

The movable arcing horn may dynamic forces and additionally, or instead, be driven by other drive elements such as, for example, by pretensioned springs or propellants; where a chemical propellant is used, it may be triggered by phenomena associated with the are, for example, a decrease in voltage, or the generation of a magnetic field, or the like.

With the above and other objects of the invention in view, the invention consists in the novel construction, arrangement and combination of various devices, elements and parts, as set forth in the claims hereof, certain embodiillustrated in the accompanying drawings and described in the specification.

In the accompanying drawings,

FIG. 1 is a fragmentary elevational view, partly in section, of a protective ring in accordance with the invention, including a movable arcing horn that is blocked by an arresting pin;

FIG. 2 is a .plan view thereof, partly in section;

FIG. 3 is a fragmentary elevational view, partly in section, similar to FIG. 1, but embodying a modification;

FIG. 4 is a fragmentary elevational view, partly. in section, similar to FIG. 1, tion; and

FIG. 5 is a fragmentary elevational view, partly in section, similar to FIG. 1, but embodying a still further modification.

In carrying the invention into effect in the embodiments which have been selected for illustration in the accomdescription in this specification, and referring now particularly to FIGS. 1 and 2, there is provided a conductor 1 that conducts the electric current. The conductor 1 is suspended from a clamp 2 which, in turn, is supported by a pin 3, that is connected to a cup 4 of the insulator chain 5 that forms a part ofan overhead electric power transmission line.

The upper end (not shown) of the insulator chain 5 is suspended from a. crossbar of a pole or mast, and near the crossbar there is provided a conventional armature, preferably of spiral shape (not shown). A two-armed lever 6 is in a well-known manner secured with its lower end to the pin 3, and is secured near its upper end to the protective ring 7 to support it. At the point where the arm 6 is secured to the protective ring 7, the protective ring 7 is split (FIGS. 1 and 2). The protective ring 7, moreover, carries insulations 16 (FIG. 2), so that the arm 6 is secured to the protective ring 7 only mechani cally, but is not interconnected thereto electrically.

A conducting rod 8 is electrically interconnected, and mechanically secured, near its upper end to the protective ring 7 at a point diametrically opposite to the connection between the arm '6 and the protective ring 7. The conducting rod 8, similar to the lever 6, extends from the ring 7 downwardly and thence is bent at an obtuse angle and projectsv horizontally, and is connected with its far end be driven by electrobut showing a further modificato the movable end of an'arcing horn 9 in the inactive normal position thereof. The horizontal portion of the conducting rod, as best shown in FIG. 2, skirts the cup 4; no part of the conducting rod 8 makes any contact with the two-armed lever *6.

The arcing horn 9 is movable, namely tiltable about its pivot in the protective ring 7 as a fulcrum; in the aforesaid normal inactive position the arcing horn is releasably connected to the end of the conducting rod 8, namely by means of an arresting fuse pin 10. The arresting fuse pin 10 is so arranged that it will melt and thereby release for rotational movement the arcing horn 9'when current of sufiicient amperage passes through the arresting fuse pin 10.

The operation of the above described embodiment is as follows: I

When an arc is formed on the protective ring 7, the current will pass through the two-armed lever 6, the

arcing horn 9, the arresting fuse pin 10, the conducting rod 8, to the protective ring 7. Upon the occurrence of a predetermined 'curr e'n't value, the arresting fuse pin 10 will melt. Thereupon, the elEtro-dynamic forces, which are effective between the two-armed leverfiand the arcing horn 9, will rotate the tiltable arcing horn 9 from its normal inactive position (shown in solid lines in FIG. 1) to the active position 9a (shown in broken lines in FIG. 1), throughout a semicircular path indicated schematically in FIG. 1. In the active position 9a, the arc will burn steadily from the free end of the arcing horn 9.

During the rotation of the arcing horn 9, a subsidiary arc will have formed between the end of the conducting rod 8 and the end of the arcing horn 9; this are will, however, become extinguished as soon as the main arc reaches the free end .of the arcing horn 9 as the latter is tilted to the active position 9a. The aforesaid subsidiary arc promotes the transfer of the main arc to the arcing born 9.

The modification of FIG. 3 shows the same principle as FIG. 1, but the tilting of the arcing horn 9 is aided by a tension spring 11 that extends between a point of the two-armed lever 6 and an extension of the arcing horn 9.

In FIG. 4, there is shown a further modification. The arcing horn 9 is again tiltably connected to the protective ring 7, and is again not insulated therefrom electrically. The arcing horn 9 is held in the normal inactive position of FIG. 4 by gravity.

In contrast to the preceding embodiments, however, a

two-armed lever 6b is disposed diametrically oppositely of the arcing horn 9, and the lever 6a is connected near its lower end to the pin 3, and near its upper end is secured to the protective ring 7. In contrast to the previous embodiments, furthermore, the two-armed lever 6b is not insulated from the ring 7, but is interconnected electrically thereto. A tiltable lever 13 is pivoted at the point of connection of the lever 6b to the ring 7 and is electrically interconnected thereto. The free end of the tiltable lever 13 bears against an insulation 14 that separates the two-armed lever 6b from the tiltable lever 13. A connecting rod 15 connects the free end of the tiltable lever 13 with an extension 912 that is formed on the arcing horn 9.

The operation of the modification of FIG. 4 is as fol lows:

When an arc is formed on the protective ring 7 it will, owing to its one-Way feeding, have the tendency to be transferred to the extension 9b. At that extension 9b, the arc will be fed by current from the two-armed lever 6b, the tiltable lever 13 and the connecting rod 15.

- The electrodynamic effect of this current, however, will cause the tilt-able lever 13 to be turned clockwise, away from its position adjacent the two-armed lever 6b; by means of the connecting rod 15, this clockwise movement of the til-table lever 13 will be transmitted to the arcing horn 9 which, like in the previous embodiments,

will be rotated counter-clockwise from-the inactive position (illustrated in FIG. 4) to the active position (not shown); thereby, the arc will be taken on by the arcing horn 9 and will burn from the free end of the arcing horn 9 in its active position.

A difierent modification is shown in FIG. 5, wherein the arcing horn, instead of rotating, moves back and forth telescopically linearly.

To the pin 3 there is again connected a two-armed lever 60, the upper arm of which is secured to the protective ring 7 and electrically interconnected thereto. The lower arm of the lever 6c, which is parallel to the central plane of the protective ring 7, includes a projection 6a that is bent upwardly. A tube 17 is threaded onto and electrically interconnected to the projection 6a, and extends with its upper end to a point midway of the protective ring diametrically opposite the point at which the upper arm of the lever 6c is connected to the ring 7. Inside the tube 17 there is a chamber.

A rod-like arcing horn 9c is disposed in the chamber of the tube 17 and movable axially between an inactive position wherein the entire rod is confined within the tube 17 (as shown in solid lines in FIG. 5) and an active position wherein the major portion of the rod extends upwardly and projects beyond the confines of the tube 17 (shown in broken lines in FIG. 5). The arcing horn 9c has at its lower end an enlarged portion which joins the rod of the horn 9c conically, and which forms a piston 9d that is movable between upper and lower stations in the chamber of the tube 17. In all'positions of the arcing horn 9c, the piston 9d is confined to the interior of the tube 17. The piston 9d has awidth that corresponds to that of the chamber of the tube 17, and the upper end of the chamber of the tube 17 has a tapered contour that matches that of the tapered upper end of said piston 9d, so that in the upper, active position of the arcing horn 9c, the piston 9d will wedge frictionally in the upper end of the chamber of the tube 17 and make electric contact with the tube 17.

Between the lower end of the piston 9d and the upper end of the projection 6a, there is disposed a propellant 18 to which there is connected a glow-igniting device that is arranged in auxiliary electric circuit in parallel with the two-armed lever 60. That circuit electrically interconnects leads 19 and 20 which connect the glowigniting device with the projection 6a and with the upper arm of the lever 60.

In the normal inactive position, the arcing horn 9c is in the position shown in solid lines in FIG. 5, wherein the piston 9d is positioned in the lower station close to the propellant 18, while the upper end of the arcing horn 9c closes the upper opening of the tube 17. The tube 17 is electrically insulated as against the protective ring 7. Neither the tube 17 nor in its inactive position the arcing horn 9c protrude upwardly beyond the contour of the protective ring 7. e

The cap 21, for example, composed of thin synthetic material, closes the upper opening of the tube 17 to prevent the entry of moisture into the chamber.

The operation of the above described modification of FIG. 5 is as follows:

As soon as an. arc is formed on the protective ring 7, an electric current will flow through the lever 60; A portion of that current will flow through the glow-igniter that is arranged in the auxiliary circuit in parallel with the arm 6c, and thereby the propellant 18 will be ignited. Thereupon, the propellant 18 will force the piston 9d upwardly, and the upper end of the arcing horn 9c will pierce the cap 21, and the arcing horn Will proceed until the piston 9d in the upper station engages the upper end of the chamber of the tube 17. In that position, which is the active position of the arcing horn, the arcing horn will protrude beyond the upper confines of the protective ring 7. The friction between movable parts and the tube 17 is such that at once the arcing'horn 9c will be retained in the active position and be electrically conductively interconnected to the tube 17.

A small bore 17a interconnects the chamber with the exterior of the tube 17, and serves for pressure equalization. Means (not shown) may be provided for covering I the bore 17a to prevent the entry of moisture into the chamber. After the arcing horn 90 has been moved into the active position, the arc will continue to burn from the upper end of the arcing horn 90.

We wish it to be understood that we do not desire to be limited to the exact details of construction shown and described, for obvious modifications will occur to a person skilled in the art.

Having thus described the invention, what we claim as new and desire to be secured by Letters Patent is as follows:

1. An arc protector, for use in connection with an insulator suspended from the crossbar of a pole and supporting a conductor of an overhead high voltage electric power transmission line having an armature disposed near said crossbar, comprising a split protective ring adapted to be supported with relation from said insulator near said conductor and including an arcing horn movable between a normal inactive position wherein said arcing horn is disposed in the shadow of the electric field and has maximally little effect with regard to the start of the corona, and an active position, wherein upon the occurrence of a flash-overthe arc will be taken on by the free end of the movable arcing horn, said arcing horn moving from the inactive position to the active position upon the occurrence of the flashover.

2. An arc protector, as claimed in claim 1, said movable arcing horn being pivoted to, though electrically insulated from, said protective ring between the ends of said ring near the split thereof and being tiltable about said pivot in a plane radially of said protective ring.

3. An arc protector, as claimed in claim 1, said arcing horn being telescopically movable.

4. An arc protector, as claimed in claim 1, a tube uprightly adjacent a portion of said protective ring and defining on its interior an elongated chamber and having an upper passage forming an 'intercommunication between the upper portion of said chamber and the exterior of said tube, a piston including a rod forming said arcing horn movable in said chamber between a lower station, wherein said arcing horn is in the inactive position and confined in said tube, and an upper station, wherein said arcing horn is in the active position and projects beyond said tube, a propellant disposed in said chamber below said piston in the lower station thereof, and an auxiliary electric circuit operable to be energized during flashover thereby igniting said propellant.

5. An arc protector, as claim in claim 4, the upper portion of said chamber having a tapered contour matching that of the upper portion of said piston, whereby in the upper station the piston will wedge against said tube and make electrical contact therewith.

6. An arc protector, as claimed in claim 1, a conducting member connected to said protective ring, an arresting pin connecting said arcing horn to said conducting member in the inactive position of the arcing horn, whereby, upon the occurrence of a flashover, electric current will pass throughsaid conductor and through said arresting pin and through said arcing horn, said arresting pin melting upon the attainment of a predetermined value by said current there-by releasing said arcing horn for movement from said inactive position to said active position.

7. An arc protector, as claimed in claim 6, and a tension spring urging said arcing horn into the active position, and accelerating the arcing horn upon its release by the melting of the arresting pin.

8. An arc protector, for use in connection with an insulator suspended from the crossbar of a pole and supporting a conductor of an overhead high voltage electric power transmission line having an armature disposed near said crossbar, comprising a protective ring adapted to be supported with relation from said insulator near said conductor and including a plurality of members, at least one of said members being movable, and at least one-other member being stationary and connected to said conductor and supporting said protective ring and being electrically interconnected to said conductor and to said protective ring and having an upright portion, said movable member normally being positioned adjacent said upright portion of said stationary member and being operable upon the occurrence of a flashover to be moved from said normal position to a position at an angle thereto, electric current flowing during the occurrence of said flashover through said stationary member and said movable member in opposite directions.

9. An arc protector, as claimed in claim 8, another of said members being movableand constituting an arcing horn and being mechanically connected and electrically interconnected to said one movable member, the electric current upon the occurrence of a flashover flowing through said two movable members in opposite directions.

10. In an arc protector system, for use in connection with an overhead high voltage electric power transmission line having poles and crossbars, the combination with an insulator suspended from the cross-bar of a pole and supporting a conductor of the line and having an .a normal inactive armature disposed near said crossbar, of a split protective ring supported with relation from said insulator near said conductor and including an arcing horn movable between position wherein said arcing horn is disposed in the shadow of the electric field and has maximally little effect with regard to the start of the corona, and an active position, wherein upon the occurrence of a flashover the arc will be taken on by the free end of the movable arcing horn, said arcing horn moving from the inactive position to the active position upon the occurrence of the flashover.

References Cited by the Examiner UNITED STATES PATENTS 1,690,200 11/1928 Miller 1,972,613

174141 9/1934 Austin 31772 X 

1. AN ARC PROTECTOR, FOR USE IN CONNECTION WITH AN INSULATOR SUSPENDED FROM THE CROSSBAR OF A POLE AND SUPPORTING A CONDUCTOR OF AN OVERHEAD HIGH VOLTAGE ELECTRIC POWER TRANSMISSION LINE HAVING AN ARMATURE DISPOSED NEAR SAID CROSSBAR, COMPRISING A SPLIT PROTECTIVE RING ADAPTED TO BE SUPPORTED WITH RELATION FROM SAID INSULATOR NEAR SAID CONDUCTOR AND INCLUDING AN ARCING HORN MOVABLE BETWEEN A NORMAL INACTIVE POSITION WHEREIN SAID ARCING HORN IS DISPOSED IN THE SHADOW OF THE ELECTRIC FIELD AND HAS MAXIMALLY LITTLE EFFECT WITH REGARD TO THE START OF THE CORONA, AND AN ACTIVE POSITION, WHEREIN UPON THE OCCURRENCE OF A FLASHOVER THE ARC WILL BE TAKEN ON BY THE FREE END OF THE MOVABLE ARCING HORN, SAID ARCING HORN MOVING FROM THE INACTIVE POSITION TO THE ACTIVE POSITION UPON THE OCCURRENCE OF THE FLASHOVER. 